Large-scale disease patterns explained by climatic seasonality and host traits.

Understanding factors affecting the distribution of vector-borne diseases in space and across species is of prime importance to conservation ecologists. Identifying the underlying patterns of disease requires a perspective encompassing large spatial scales. However, few studies have investigated disease ecology from a macroecological perspective. Hence, we use a global disease database to uncover worldwide infection patterns using avian malaria (Plasmodium) as a model for vector-borne disease transmission. Using data on 678 bird species from 442 locations, we show that environmental variables likely to synchronize bird and vector abundance are the key factors dictating infection risk for birds. Moreover, direct effects of host traits on exposure risk as well as potential trade-offs in resource allocation were also shown to affect disease susceptibility, with larger bird species being more prone to infection. Our results suggest that considering evolutionary strategies and factors influencing spatial overlap between hosts and vectors is crucial for understanding worldwide patterns of disease transmission success.